Methods and devices for multi-connection transmission

ABSTRACT

A method in a terminal device for transmission to at least a first network device and a second network device over bundled Transmission Time Intervals (TTIs). The method comprises determining that a first TTI for transmission to the first network device overlaps a second TTI for transmission to the second network device based on a first Timing Advance (TA) value associated with the first network device and a second TA value associated with the second network device; and blanking a portion of the first TTI, such that the rest of the first TTI does not overlap the second TTI.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 16/740,363,filed Jan. 10, 2020, which is a continuation of application Ser. No.15/502,181, filed Feb. 6, 2017 (now U.S. Pat. No. 10,536,961 issued Jan.14, 2020), which is a National stage of International Application No.PCT/CN2016/113715, filed Dec. 30, 2016, which are all herebyincorporated by reference.

TECHNICAL FIELD

The present disclosure relates to communication technology, and moreparticularly, to methods and devices for multi-connection transmission,e.g., transmission to two or more network devices over bundledTransmission Time Intervals (TTIs).

BACKGROUND ART

Ultra-Reliable and Low-Latency Communications (URLLC) is a category ofservices defined in 3GPP TR 22.862, Version 14.1.0. For URLLC services,both high reliability and low latency are required. However, theserequirements are mutually conflicting and are typically traded offagainst each other, which brings a remarkable challenge to user-plane(UP) design.

According to 3GPP TR 22.862, the latency requirement for URLLC servicesranges from 1 ms to 10 ms for various applications including automationapplications, smart grids and intelligent transportation. Thereliability requirement for URLLC services ranges from a residual errorrate of 10⁻⁴ to 10⁻⁶, or even to 10⁻⁹. It is to be noted here that incalculating the residual error rate, packets arriving later than therequired latency bound, such as 1 ms or 10 ms, will be regarded aserrors in the context of URLLC.

Simultaneously achieving such high requirements on both reliability andlatency may affect several layers and components in both Radio AccessNetwork (RAN) and Core Network (CN). The URLLC can be considered as anextremely high Quality of Service (QoS) use case for both RAN and CN.

In order to meet the above requirements, it has been proposed to providea terminal device (e.g., a User Equipment, or UE) with multipleconnections to multiple network devices (e.g., evolved NodeBs (eNBs)).This is particularly useful when the terminal device is communicatingtime-critical data and/or is in poor network coverage (e.g., at celledge), since the diversity gain provided by the multiple connections canbe fully exploited.

FIG. 1 shows an exemplary scenario where such multi-connectiontransmission is deployed. As shown, a terminal device 110 has uplink(UL) connections with three network devices 120, 122 and 124. Inparticular, the terminal device 110 transmits UL data to the networkdevices 120, 122 and 124 over bundled Transmission Time Intervals(TTIs). Successive TTIs are bundled for improving transmissionreliability, with each TTI for transmitting the same information toachieve a transmission diversity gain. In the example shown in FIG. 1 ,six successive TTIs are bundled. The first three of the TTIs, labeled as1-1, 1-2 and 1-3, are allocated for transmission towards the networkdevice 120, the following two TTIs, labeled as 2-1 and 2-2, fortransmission towards the network device 122, and the last TTI, labeledas 3, for transmission towards the network device 124. Optionally, aflexible beamforming scheme can be adopted at the terminal device 110,such that the transmissions towards the network devices 120, 122 and 124can be carried out via different beams (B1, B2 and B3 as shown in FIG. 1), respectively.

In order to achieve UL synchronization at a network device, a TimingAdvance (TA) value is configured for a terminal device for ULtransmission towards the network device. However, in themulti-connection transmission scenario, different TA values fordifferent network devices at one single terminal device may becomeproblematic.

FIG. 2 shows an exemplary TA configuration for a terminal device (e.g.,the terminal device 110) in a multi-connection transmission scenario(e.g., the scenario shown in FIG. 1 ). The uppermost line of FIG. 2shows UL timing at each of the network devices 120, 122 and 124 (it isassumed here that the network devices 120, 122 and 124 have theiruplinks synchronized with each other). The three lines below showrespective UL transmission timings for the network devices 120, 122 and124 at the terminal device 110. The TA values for the network devices120, 122 and 124 are denoted as TA1, TA2 and TA3, respectively and it isassumed here that TA2>TA1>TA3. It can be seen from FIG. 2 that a portionof the last TTI 1-3 for transmission to the network device 120 overlapsa portion of the first TTI 2-1 for transmission to the network device122 in time, as shown in the hatched regions. That is, since TA2 islarger than TA1, the transmission to the network device 122 is scheduledto begin before the transmission to the network device 120 ends. This isnot possible for the terminal device 110 if it has only one radio unit,especially when the beamforming is applied.

There is thus a need for an improved solution for multi-connectiontransmission with different TA values.

SUMMARY OF THE INVENTION

It is an object of the present disclosure to provide methods and devicesfor multi-connection transmission, capable of solving the above problemassociated with different TA values.

In a first aspect of the present disclosure, a method in a terminaldevice for transmission to at least a first network device and a secondnetwork device over bundled Transmission Time Intervals (TTIs) isprovided. The method comprises: determining that a first TTI fortransmission to the first network device overlaps a second TTI fortransmission to the second network device based on a first TimingAdvance, TA, value associated with the first network device and a secondTA value associated with the second network device; and blanking aportion of the first TTI, such that the rest of the first TTI does notoverlap the second TTI.

In an embodiment, the step of determining comprises determining that thefirst TTI overlaps the second TTI when: the first TTI precedes thesecond TTI and the first TA value is smaller than the second TA value,or the first TTI follows the second TTI and the first TA value is largerthan the second TA value.

In an embodiment, the blanking is in response to the first networkdevice having a higher received signal power than the second networkdevice at the terminal device.

In an embodiment, the blanking is in response to the transmission to thefirst network device having a larger number of TTIs than thetransmission to the second network device among the bundled TTIs.

In an embodiment, the blanked portion has a length that is a pluralityof Orthogonal Frequency Division Multiplexing (OFDM) symbols.

In an embodiment, the method further comprises: notifying the firstnetwork device of the blanking of the portion.

In an embodiment, the method further comprises: blanking a portion ofthe second TTI, such that the rest of the first TTI does not overlap therest of the second TTI.

In a second aspect of the present disclosure, a terminal device fortransmission to at least a first network device and a second networkdevice over bundled Transmission Time Intervals (TTIs) is provided. Theterminal device comprises: a determining unit configured to determinethat a first TTI for transmission to the first network device overlaps asecond TTI for transmission to the second network device based on afirst Timing Advance, TA, value associated with the first network deviceand a second TA value associated with the second network device; and ablanking unit configured to blank a portion of the first TTI, such thatthe rest of the first TTI does not overlap the second TTI.

In a third aspect of the present disclosure, a terminal device fortransmission to at least a first network device and a second networkdevice over bundled Transmission Time Intervals, TTIs is provided. Theterminal device comprises a transceiver, a processor and a memory, thememory containing instructions executable by the processor whereby theterminal device is operative to perform the method according to theabove first aspect.

The above embodiments of the first aspect are also applicable for thesecond and third aspects.

In a fourth aspect of the present disclosure, a method in a networkdevice for facilitating transmission from a terminal device to thenetwork device and at least another network device over bundledTransmission Time Intervals (TTIs) is provided. The method comprises:receiving from the terminal device a first TTI having a portion blankedfor avoiding overlap with a second TTI for transmission to the othernetwork device; obtaining knowledge of the blanked portion; and decodingthe first TTI with the obtained knowledge of the blanked portion.

In an embodiment, the knowledge of the blanked portion is obtained byreceiving a notification regarding the blanked portion from the terminaldevice.

In an embodiment, the knowledge of the blanked portion is obtained basedon a position of a reference signal in the first TTI.

In an embodiment, the knowledge of the blanked portion is obtained basedon a received signal power during the first TTI.

In an embodiment, the blanked portion has a length that is a pluralityof Orthogonal Frequency Division Multiplexing (OFDM) symbols.

In a fifth aspect of the present disclosure, a network device forfacilitating transmission from a terminal device to the network deviceand at least another network device over bundled Transmission TimeIntervals (TTIs) is provided. The network device comprises: a receivingunit configured to receive from the terminal device a first TTI having aportion blanked for avoiding overlap with a second TTI for transmissionto the other network device; an obtaining unit configured to obtainknowledge of the blanked portion; and a decoding unit configured todecode the first TTI with the obtained knowledge of the blanked portion.

In a sixth aspect of the present disclosure, a network device forfacilitating transmission from a terminal device to the network deviceand at least another network device over bundled Transmission TimeIntervals (TTIs) is provided. The network device comprises atransceiver, a processor and a memory, the memory containinginstructions executable by the processor whereby the network device isoperative to perform the method according to the above fourth aspect.

The above embodiments of the fourth aspect are also applicable for thefifth and sixth aspects.

In a seventh aspect of the present disclosure, a method in a terminaldevice for transmission to at least a first network device and a secondnetwork device over bundled Transmission Time Intervals (TTIs) isprovided. The method comprises: determining that a first TTI fortransmission to the first network device overlaps a second TTI fortransmission to the second network device based on a first TimingAdvance, TA, value associated with the first network device and a secondTA value associated with the second network device; requesting from thefirst and second network devices a first and a second transmissiongrants, respectively, each determined based on the first and second TAvalues; receiving the first and second transmission grants from thefirst and second network devices, respectively; and transmitting data tothe first and second network devices in accordance with the first andsecond transmission grants, respectively.

In an embodiment, the step of determining comprises: determining thatthe first TTI overlaps the second TTI when the first TTI precedes thesecond TTI and the first TA value is smaller than the second TA value,or the first TTI follows the second TTI and the first TA value is largerthan the second TA value.

In an embodiment, the step of requesting comprises: transmitting thefirst and second TA values to each of the first and second networkdevices.

In an embodiment, the step of requesting comprises: requesting the firstand second transmission grants in an order determined based on the firstand second TA values.

In an embodiment, the transmission to the first network device scheduledby the first transmission grant occurs prior to the transmission to thesecond network device scheduled by the second transmission grant whenthe first TA value is larger than the second TA value, or thetransmission to the first network device scheduled by the firsttransmission grant occurs after the transmission to the second networkdevice scheduled by the second transmission grant when the first TAvalue is smaller than the second TA value.

In an eighth aspect of the present disclosure, a terminal device fortransmission to at least a first network device and a second networkdevice over bundled Transmission Time Intervals (TTIs) is provided. Theterminal device comprises: a determining unit configured to determinethat a first TTI for transmission to the first network device overlaps asecond TTI for transmission to the second network device based on afirst Timing Advance, TA, value associated with the first network deviceand a second TA value associated with the second network device; arequesting unit configured to request from the first and second networkdevices a first and a second transmission grants, respectively, eachdetermined based on the first and second TA values; a receiving unitconfigured to receive the first and second transmission grants from thefirst and second network devices, respectively; and a transmitting unitconfigured to transmit data to the first and second network devices inaccordance with the first and second transmission grants, respectively.

In a ninth aspect of the present disclosure, a terminal device fortransmission to at least a first network device and a second networkdevice over bundled Transmission Time Intervals (TTIs) is provided. Theterminal device comprises a transceiver, a processor and a memory, thememory containing instructions executable by the processor whereby theterminal device is operative to perform the method according to theabove seventh aspect.

In a tenth aspect of the present disclosure, a method in a networkdevice for facilitating transmission from a terminal device to thenetwork device and at least another network device over bundledTransmission Time Intervals (TTIs) is provided. The method comprises:obtaining a first Timing Advance, TA, value associated with the networkdevice and a second TA value associated with the other network device;determining a first transmission grant associated with the networkdevice and a second transmission grant associated with the other networkdevice based on the first and second TA values, such that any TTI fortransmission to the network device to be scheduled by the firsttransmission grant does not overlap any TTI for transmission to theother network device to be scheduled by the second transmission grant;and transmitting the first and second transmission grants to theterminal device.

In an embodiment, the first and second transmission grants aredetermined such that: the transmission to the first network devicescheduled by the first transmission grant occurs prior to thetransmission to the second network device scheduled by the secondtransmission grant when the first TA value is larger than the second TAvalue, or the transmission to the first network device scheduled by thefirst transmission grant occurs after the transmission to the secondnetwork device scheduled by the second transmission grant when the firstTA value is smaller than the second TA value.

In an embodiment, the step of transmitting the second transmission grantto the terminal device comprises: transmitting the second transmissiongrant to the second network device for forwarding to the terminaldevice.

In an eleventh aspect of the present disclosure, a network device forfacilitating transmission from a terminal device to the network deviceand at least another network device over bundled Transmission TimeIntervals (TTIs) is provided. The network device comprises: an obtainingunit configured to obtain a first Timing Advance, TA, value associatedwith the network device and a second TA value associated with the othernetwork device; a determining unit configured to determine a firsttransmission grant associated with the network device and a secondtransmission grant associated with the other network device based on thefirst and second TA values, such that any TTI for transmission to thenetwork device to be scheduled by the first transmission grant does notoverlap any TTI for transmission to the other network device to bescheduled by the second transmission grant; and a transmitting unitconfigured to transmit the first and second transmission grants to theterminal device.

In a twelfth aspect of the present disclosure, a network device forfacilitating transmission from a terminal device to the network deviceand at least another network device over bundled Transmission TimeIntervals (TTIs) is provided. The network device comprises atransceiver, a processor and a memory, the memory containinginstructions executable by the processor whereby the network device isoperative to perform the method according to the above tenth aspect.

With the embodiments of the present disclosure, the overlap betweenneighboring TTIs for transmission towards different network devices canbe avoided and thus the reliability of UL transmission can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages will be moreapparent from the following description of embodiments with reference tothe figures, in which:

FIG. 1 is a schematic diagram showing an exemplary scenario ofmulti-connection transmission;

FIG. 2 is a schematic diagram showing an exemplary TA configuration fora terminal device;

FIG. 3 is a flowchart illustrating a method in a terminal deviceaccording to an embodiment of the present disclosure;

FIG. 4 is a flowchart illustrating a method in a network deviceaccording to an embodiment of the present disclosure;

FIG. 5 is a flowchart illustrating a method in a terminal deviceaccording to another embodiment of the present disclosure;

FIG. 6 is a flowchart illustrating a method in a network deviceaccording to another embodiment of the present disclosure;

FIG. 7 is a schematic diagram showing re-ordering of the TTIs in FIG. 2according to the method shown in FIG. 5 or 6 ;

FIG. 8 is a block diagram of a terminal device according to anembodiment of the present disclosure;

FIG. 9 is a block diagram of a terminal device according to anotherembodiment of the present disclosure;

FIG. 10 is a block diagram of a network device according to anembodiment of the present disclosure;

FIG. 11 is a block diagram of a network device according to anotherembodiment of the present disclosure;

FIG. 12 is a block diagram of a terminal device according to yet anotherembodiment of the present disclosure; and

FIG. 13 is a block diagram of a network device according to yet anotherembodiment of the present disclosure.

DETAILED DESCRIPTION

The embodiments of the disclosure will be detailed below with referenceto the drawings. It should be appreciated that the following embodimentsare illustrative only, rather than limiting the scope of the disclosure.

FIG. 3 is a flowchart illustrating a method 300 in a terminal device(e.g., the terminal device 110 in FIG. 1 ) for transmission to at leasta first network device (e.g., the network device 120 or 122 in FIG. 1 )and a second network device (e.g., the network device 122 or 120 in FIG.1 ) over bundled TTIs according to an embodiment of the presentdisclosure. In the context of the present disclosure, a “TTI” refers toa basic element to be scheduled for transmission in the time domain,which can be e.g., a Transmission Time Interval with general meaning inLong Term Evolution (LTE) or a subframe as in LTE. The method 300includes the following steps.

At step S310, it is determined that a first TTI for transmission to thefirst network device overlaps a second TTI for transmission to thesecond network device based on a first TA value associated with thefirst network device and a second TA value associated with the secondnetwork device.

In an example, in the step S310, it is determined that the first TTIoverlaps the second TTI when the first TTI precedes the second TTI andthe first TA value is smaller than the second TA value, or when thefirst TTI follows the second TTI and the first TA value is larger thanthe second TA value.

At step S320, a portion of the first TTI is blanked, such that the restof the first TTI does not overlap the second TTI.

In other words, in the step S320, the portion of the first TTI isdiscarded, or punctured, without being used for transmission, so as toavoid overlap with the second TTI.

Preferably, in order to facilitate combination and demodulation/decodingat the network devices, the blanked portion may have a length that is aplurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols.

In an example, in the step S320, the portion of the first TTI can beblanked when the first network device has a higher received signal power(e.g., Reference Signal Received Power, or RSRP) than the second networkdevice at the terminal device. On the other hand, when the secondnetwork device has a higher received signal power than the first networkdevice at the terminal device, a portion of the second TTI can beblanked instead to avoid the overlapping.

Alternatively, in the step S320, the portion of the first TTI can beblanked when the transmission to the first network device has a largernumber of TTIs than the transmission to the second network device amongthe bundled TTIs. On the other hand, when the second network device hasa larger number of TTIs than the transmission to the first networkdevice among the bundled TTIs, a portion of the second TTI can beblanked instead to avoid the overlapping.

In an example, the terminal device can notify the first network deviceof the blanking of the portion. For example, the number of OFDM symbolscontained in the blanked portion may typically range from 1 to 3. Inthis case, a 1-bit or 2-bit indicator can be used to explicitly indicatethe blanked portion. With such explicit notification, the first networkdevice can be aware of the blanking and thus will not treat the blankedportion as useful information.

Additionally, a portion of the second TTI can be blanked, such that therest of the first TTI does not overlap the rest of the second TTI. Inthis case, each of the first and second TTIs may have a portion blankedto avoid the overlapping.

FIG. 4 is a flowchart illustrating a method 400 in a network device(e.g., the network device 120 or 122 in FIG. 1 ) for facilitatingtransmission from a terminal device (e.g., the terminal device 110 inFIG. 1 ) to the network device and at least another network device(e.g., the network device 122 or 120 in FIG. 1 ) over bundled TTIs. Themethod 400 includes the following steps.

At step S410, a first TTI is received from the terminal device. Thefirst TTI has a portion blanked for avoiding overlap with a second TTIfor transmission to the other network device.

As described above in connection with the method 300, preferably, theblanked portion has a length that is a plurality of OFDM symbols.

At step S420, knowledge of the blanked portion is obtained.

In an example, in the step S420, the knowledge of the blanked portioncan be obtained by receiving a notification regarding the blankedportion from the terminal device. Such explicit notification has beendescribed above in connection with the method 300 and the descriptionthereof will be omitted here.

Alternatively, the blanked portion can be detected blindly by thenetwork device. In an example, the knowledge of the blanked portion canbe obtained based on a position of a reference signal in the first TTI.The position of the reference signal in the first TTI can bepredetermined and known to the network device. The network device candetect the blanked portion based on the position of the reference signalin the received TTI. For example, the reference signal can betransmitted at a fixed position, e.g., in the third OFDM symbol in theTTI. In this case, if the network device receives the TTI having thereference signal in the first OFDM symbol, it can determine that thefirst two OFDM symbols of the TTI have been blanked.

In another example, the knowledge of the blanked portion can be obtainedbased on a received signal power during the first TTI. For example, thenetwork device can detect the start and/or end of the TTI based on thereceived signal power during the TTI. As an example, if a particularportion of the TTI has a lower received signal power than the rest ofthe TTI by at least a threshold, the network device can determine thatthe particular portion has been blanked.

At step S430, the first TTI is decoded with the obtained knowledge ofthe blanked portion. That is, the network device will not treat theblanked portion as useful information.

It is to be noted here that the blanking of the portion does not preventthe information which would otherwise be carried in that portion frombeing detected. First, the information may be protected by means oferror correction coding with a high redundancy (i.e., a low coding rate)and the corresponding information bits may be interleaved before coding.Second, each of the bundled TTIs may carry the same information forachieving a transmission diversity gain, as described above.Accordingly, the TTIs can be selectively combined at the network devicesfor successful detection of the carried information.

The methods 300 and 400 will be further explained with reference to FIG.2 . In the example shown in FIG. 2 , the terminal device 110 maydetermine that the last TTI 1-3 for transmission to the network device120 overlaps the first TTI 2-1 for transmission to the network device122, since TA2>TA1. Then, the terminal device 110 may decide to blank aportion (e.g., the hatched portion) of the TTI 1-3 to avoid theoverlapping, e.g., in response to the network device 120 having a higherRSRP than the network device 122 at the terminal device 110, or thetransmission to the network device 120 having a larger number of TTIsthan the transmission to the network device 122 (3 vs. 2). Optionally,the terminal device 110 can explicitly notify the network device 120 ofthe blanking. (Alternatively, the terminal device 110 may decide toblank a portion (e.g., the hatched portion) of the TTI 2-1 to avoid theoverlapping, and notify the network device 122 accordingly.)

The network device 120 receives the TTIs 1-1, 1-2, and 1-3 and knowsthat the TTI 1-3 has a portion blanked, e.g., by receiving an explicitnotification from the terminal device 110 or detecting the blankedportion blindly as described above. Then, the network device 120 willnot treat the blanked portion as useful information in decoding theTTIs.

FIG. 5 is a flowchart illustrating a method 500 in a terminal device(e.g., the terminal device 110 in FIG. 1 ) for transmission to at leasta first network device (e.g., the network device 120 or 122 in FIG. 1 )and a second network device (e.g., the network device 122 or 120 in FIG.1 ) over bundled TTIs according to an embodiment of the presentdisclosure. The method 500 includes the following steps.

At step S510, it is determined that a first TTI for transmission to thefirst network device overlaps a second TTI for transmission to thesecond network device based on a first TA value associated with thefirst network device and a second TA value associated with the secondnetwork device. As in the step S310, it can be determined here that thefirst TTI overlaps the second TTI when the first TTI precedes the secondTTI and the first TA value is smaller than the second TA value, or whenthe first TTI follows the second TTI and the first TA value is largerthan the second TA value.

At step S520, a first and a second transmission grants are requestedfrom the first and second network devices, respectively, based on thefirst and second TA values.

In the step S520, the first and second TA values can be transmitted toeach of the first and second network devices, such that the first andsecond network devices can determine the first and second transmissiongrants, respectively, based on the first and second TA values.

Alternatively, the terminal device may request the first and secondtransmission grants in an order determined based on the first and secondTA values, such that the network device may determine and transmit thefirst and second transmission grants in the order determined based onthe first and second TA values. For example, if the first TA value islarger than the second TA value, then the terminal device may requestthe first transmission grant for transmission to the first networkdevice earlier than requesting of the second transmission grant fortransmission to the second network device.

At step S530, the first and second transmission grants are received fromthe first and second network devices, respectively.

At step S540, data is transmitted to the first and second networkdevices in accordance with the first and second transmission grants,respectively.

Here, in order to avoid the overlapping, the transmission to the firstnetwork device scheduled by the first transmission grant can occur priorto the transmission to the second network device scheduled by the secondtransmission grant when the first TA value is larger than the second TAvalue. Alternatively, the transmission to the first network devicescheduled by the first transmission grant can occur after thetransmission to the second network device scheduled by the secondtransmission grant when the first TA value is smaller than the second TAvalue.

In order words, the transmission grants can be determined by the networkdevices such that the transmission associated with a larger TA value canbe scheduled to occur earlier. In this way, the overlapping between TTIscan be avoided.

FIG. 6 is a flowchart illustrating a method 600 in a network device(e.g., the network device 120 or 122 in FIG. 1 ) for facilitatingtransmission from a terminal device (e.g., the terminal device 110 inFIG. 1 ) to the network device and at least another network device(e.g., the network device 122 or 120 in FIG. 1 ) over bundled TTIs. Inan example, the method 600 can be performed in a coordinating entityprovided in the network device for coordinating UL transmission grantsacross network devices. The method 600 includes the following steps.

At step S610, a first TA value associated with the network device and asecond TA value associated with the other network device are obtained.For example, the first TA value can be obtained by measuring a PhysicalRandom Access Channel (PRACH) from the terminal device locally at thenetwork device. The second TA value can be received from the othernetwork device or a coordinating entity for coordinating UL transmissiongrants across the network devices. As another example, the terminaldevice can obtain the first TA value and the second TA value from thenetwork device and the other network device, respectively, and thentransmit them to the network device.

Ata step S620, a first transmission grant associated with the networkdevice and a second transmission grant associated with the other networkdevice are determined based on the first and second TA values, such thatany TTI for transmission to the network device to be scheduled by thefirst transmission grant does not overlap any TTI for transmission tothe other network device to be scheduled by the second transmissiongrant. As described above in connection with the method 500, the firstand second transmission grants are determined such that: thetransmission to the first network device scheduled by the firsttransmission grant occurs prior to the transmission to the secondnetwork device scheduled by the second transmission grant when the firstTA value is larger than the second TA value, or the transmission to thefirst network device scheduled by the first transmission grant occursafter the transmission to the second network device scheduled by thesecond transmission grant when the first TA value is smaller than thesecond TA value. In order words, the transmission grants can bedetermined such that the transmission associated with a larger TA valuecan be scheduled to occur earlier. In this way, the overlapping betweenTTIs can be avoided.

At step S630, the first and second transmission grants are transmittedto the terminal device.

In an example, the second transmission grant can be transmitted to thesecond network device, which then forwards it to the terminal device.

FIG. 7 shows re-ordering of the TTIs in FIG. 2 according to the method500 or 600. As shown, in accordance with the rule that a transmissionassociated with a larger TA value shall be scheduled to occur earlier,the TTIs 2-1 and 2-2 associated with the largest TA value, TA2, arescheduled to occur first in the bundled TTIs. They are followed by theTTIs 1-1, 1-2 and 1-3 associated with TA1, which are in turn followed bythe TTI 3 associated with the smallest TA value, TA3. It can be seenfrom FIG. 7 that any overlapping between TTIs can be avoided in thisway.

Correspondingly to the method 300 as described above, a terminal deviceis provided. FIG. 8 is a block diagram of a terminal device 800 fortransmission to at least a first network device and a second networkdevice over bundled TTIs according to an embodiment of the presentdisclosure.

As shown in FIG. 8 , the terminal device 800 includes a determining unit810 configured to determine that a first TTI for transmission to thefirst network device overlaps a second TTI for transmission to thesecond network device based on a first TA value associated with thefirst network device and a second TA value associated with the secondnetwork device. The terminal device 800 further includes a blanking unit820 configured to blank a portion of the first TTI, such that the restof the first TTI does not overlap the second TTI.

In an embodiment, the determining unit 810 is configured to determinethat the first TTI overlaps the second TTI when: the first TTI precedesthe second TTI and the first TA value is smaller than the second TAvalue, or the first TTI follows the second TTI and the first TA value islarger than the second TA value.

In an embodiment, the blanking unit 820 is configured to blank theportion of the first TTI in response to the first network device havinga higher received signal power than the second network device at theterminal device.

In an embodiment, the blanking unit 820 is configured to blank theportion of the first TTI in response to the transmission to the firstnetwork device having a larger number of TTIs than the transmission tothe second network device among the bundled TTIs.

In an embodiment, the blanked portion has a length that is a pluralityof Orthogonal Frequency Division Multiplexing (OFDM) symbols.

In an embodiment, the terminal device 800 further includes a notifyingunit configured to notify the first network device of the blanking ofthe portion.

In an embodiment, the blanking unit 820 is further configured to blank aportion of the second TTI, such that the rest of the first TTI does notoverlap the rest of the second TTI.

The above units 810-820 can be implemented as a pure hardware solutionor as a combination of software and hardware, e.g., by one or more of: aprocessor or a micro-processor and adequate software and memory forstoring of the software, a Programmable Logic Device (PLD) or otherelectronic component(s) or processing circuitry configured to performthe actions described above, and illustrated, e.g., in FIG. 3 .

Correspondingly to the method 500 as described above, a terminal deviceis provided. FIG. 9 is a block diagram of a terminal device 900 fortransmission to at least a first network device and a second networkdevice over bundled TTIs according to another embodiment of the presentdisclosure.

As shown in FIG. 9 , the terminal device 900 includes a determining unit910 configured to determine that a first TTI for transmission to thefirst network device overlaps a second TTI for transmission to thesecond network device based on a first TA value associated with thefirst network device and a second TA value associated with the secondnetwork device. The terminal device 900 further includes a requestingunit 920 configured to request from the first and second network devicesa first and a second transmission grants, respectively, based on thefirst and second TA values. The terminal device 900 further includes areceiving unit 930 configured to receive the first and secondtransmission grants from the first and second network devices,respectively. The terminal device 900 further includes a transmittingunit 940 configured to transmit data to the first and second networkdevices in accordance with the first and second transmission grants,respectively.

In an embodiment, the determining unit 910 is configured to determinethat the first TTI overlaps the second TTI when the first TTI precedesthe second TTI and the first TA value is smaller than the second TAvalue, or the first TTI follows the second TTI and the first TA value islarger than the second TA value.

In an embodiment, the requesting unit 920 is further configured totransmit the first and second TA values to each of the first and secondnetwork devices.

In an embodiment, the requesting unit 920 is configured to request thefirst and second transmission grants in an order determined based on thefirst and second TA values.

In an embodiment, the transmission to the first network device scheduledby the first transmission grant occurs prior to the transmission to thesecond network device scheduled by the second transmission grant whenthe first TA value is larger than the second TA value, or thetransmission to the first network device scheduled by the firsttransmission grant occurs after the transmission to the second networkdevice scheduled by the second transmission grant when the first TAvalue is smaller than the second TA value.

The above units 910-940 can be implemented as a pure hardware solutionor as a combination of software and hardware, e.g., by one or more of: aprocessor or a micro-processor and adequate software and memory forstoring of the software, a Programmable Logic Device (PLD) or otherelectronic component(s) or processing circuitry configured to performthe actions described above, and illustrated, e.g., in FIG. 5 .

Correspondingly to the method 400 as described above, a network deviceis provided. FIG. 10 is a block diagram of a network device 1000 forfacilitating transmission from a terminal device to the network deviceand at least another network device over bundled TTIs according to anembodiment of the present disclosure.

As shown in FIG. 10 , the network device 1000 includes a receiving unit1010 configured to receive from the terminal device a first TTI having aportion blanked for avoiding overlap with a second TTI for transmissionto the other network device. The network device 1000 further includes anobtaining unit 1020 configured to obtain knowledge of the blankedportion. The network device 1000 further includes a decoding unit 1030configured to decode the first TTI with the obtained knowledge of theblanked portion.

In an embodiment, the obtaining unit 1020 is configured to obtain theknowledge of the blanked portion by receiving a notification regardingthe blanked portion from the terminal device.

In an embodiment, the obtaining unit 1020 is configured to obtain theknowledge of the blanked portion based on a position of a referencesignal in the first TTI.

In an embodiment, the obtaining unit 1020 is configured to obtain theknowledge of the blanked portion based on a received signal power duringthe first TTI.

In an embodiment, the blanked portion has a length that is a pluralityof Orthogonal Frequency Division Multiplexing (OFDM) symbols.

The above units 1010-1030 can be implemented as a pure hardware solutionor as a combination of software and hardware, e.g., by one or more of: aprocessor or a micro-processor and adequate software and memory forstoring of the software, a Programmable Logic Device (PLD) or otherelectronic component(s) or processing circuitry configured to performthe actions described above, and illustrated, e.g., in FIG. 4 .

Correspondingly to the method 600 as described above, a network deviceis provided. FIG. 11 is a block diagram of a network device 1100 forfacilitating transmission from a terminal device to the network deviceand at least another network device over bundled TTIs according toanother embodiment of the present disclosure.

As shown in FIG. 11 , the network device 1100 includes an obtaining unit1110 configured to obtain a first TA value associated with the networkdevice and a second TA value associated with the other network device.The network device 1100 further includes a determining unit 1120configured to determine a first transmission grant associated with thenetwork device and a second transmission grant associated with the othernetwork device based on the first and second TA values, such that anyTTI for transmission to the network device to be scheduled by the firsttransmission grant does not overlap any TTI for transmission to theother network device to be scheduled by the second transmission grant.The network device 1100 further includes a transmitting unit 1130configured to transmit the first and second transmission grants to theterminal device.

In an embodiment, the determining unit 1120 is configured to determinethe first and second transmission grants such that: the transmission tothe first network device scheduled by the first transmission grantoccurs prior to the transmission to the second network device scheduledby the second transmission grant when the first TA value is larger thanthe second TA value, or the transmission to the first network devicescheduled by the first transmission grant occurs after the transmissionto the second network device scheduled by the second transmission grantwhen the first TA value is smaller than the second TA value.

In an embodiment, the transmitting unit 1130 is configured to transmitthe second transmission grant to the second network device forforwarding to the terminal device.

The above units 1110-1130 can be implemented as a pure hardware solutionor as a combination of software and hardware, e.g., by one or more of: aprocessor or a micro-processor and adequate software and memory forstoring of the software, a Programmable Logic Device (PLD) or otherelectronic component(s) or processing circuitry configured to performthe actions described above, and illustrated, e.g., in FIG. 6 .

FIG. 12 is a block diagram of a terminal device 1200 according to yetanother embodiment of the present disclosure. The terminal device 1200is provided for transmission to at least a first network device and asecond network device over bundled TTIs.

The terminal device 1200 includes a transceiver 1210, a processor 1220and a memory 1230. The memory 1230 contains instructions executable bythe processor 1220 whereby the terminal device 1200 is operative toperform the actions, e.g., of the procedure described earlier inconjunction with FIG. 3 . Particularly, the memory 1230 containsinstructions executable by the processor 1220 whereby the terminaldevice 1200 is operative to: determine that a first TTI for transmissionto the first network device overlaps a second TTI for transmission tothe second network device based on a first Timing Advance, TA, valueassociated with the first network device and a second TA valueassociated with the second network device; and blank a portion of thefirst TTI, such that the rest of the first TTI does not overlap thesecond TTI.

Alternatively, the memory 1230 contains instructions executable by theprocessor 1220 whereby the terminal device 1200 is operative to performthe actions, e.g., of the procedure described earlier in conjunctionwith FIG. 5 . Particularly, the memory 1230 contains instructionsexecutable by the processor 1220 whereby the terminal device 1200 isoperative to determine that a first TTI for transmission to the firstnetwork device overlaps a second TTI for transmission to the secondnetwork device based on a first Timing Advance, TA, value associatedwith the first network device and a second TA value associated with thesecond network device; requesting from the first and second networkdevices a first and a second transmission grants, respectively, eachdetermined based on the first and second TA values; receiving the firstand second transmission grants from the first and second networkdevices, respectively; and transmitting data to the first and secondnetwork devices in accordance with the first and second transmissiongrants, respectively.

FIG. 13 is a block diagram of a network device 1300 according to yetanother embodiment of the present disclosure. The network device 1300 isprovided for facilitating transmission from a terminal device to thenetwork device and at least another network device over bundled TTIs.

The network device 1300 includes a transceiver 1310, a processor 1320and a memory 1330. The memory 1330 contains instructions executable bythe processor 1320 whereby the network device 1300 is operative toperform the actions, e.g., of the procedure described earlier inconjunction with FIG. 4 . Particularly, the memory 1330 containsinstructions executable by the processor 1320 whereby the network device1300 is operative to: receive from the terminal device a first TTIhaving a portion blanked for avoiding overlap with a second TTI fortransmission to the other network device; obtain knowledge of theblanked portion; and decode the first TTI with the obtained knowledge ofthe blanked portion.

Alternatively, the memory 1330 contains instructions executable by theprocessor 1320 whereby the network device 1300 is operative to performthe actions, e.g., of the procedure described earlier in conjunctionwith FIG. 6 . Particularly, the memory 1330 contains instructionsexecutable by the processor 1320 whereby the network device 1300 isoperative to: obtain a first TA value associated with the network deviceand a second TA value associated with the other network device;determine a first transmission grant associated with the network deviceand a second transmission grant associated with the other network devicebased on the first and second TA values, such that any TTI fortransmission to the network device to be scheduled by the firsttransmission grant does not overlap any TTI for transmission to theother network device to be scheduled by the second transmission grant;and transmit the first and second transmission grants to the terminaldevice.

The present disclosure also provides at least one computer programproduct in the form of a non-volatile or volatile memory, e.g., anon-transitory computer readable storage medium, an ElectricallyErasable Programmable Read-Only Memory (EEPROM), a flash memory and ahard drive. The computer program product includes a computer program.The computer program includes: code/computer readable instructions,which when executed by the processor 1220 causes the terminal device1200 to perform the actions, e.g., of the procedure described earlier inconjunction with FIG. 3 or 5 ; or code/computer readable instructions,which when executed by the processor 1320 causes the network device 1300to perform the actions, e.g., of the procedure described earlier inconjunction with FIG. 4 or 6 .

The computer program product may be configured as a computer programcode structured in computer program modules. The computer programmodules could essentially perform the actions of the flow illustrated inFIG. 3, 4, 5 or 6 .

The processor may be a single CPU (Central processing unit), but couldalso comprise two or more processing units. For example, the processormay include general purpose microprocessors; instruction set processorsand/or related chips sets and/or special purpose microprocessors such asApplication Specific Integrated Circuit (ASICs). The processor may alsocomprise board memory for caching purposes. The computer program may becarried by a computer program product connected to the processor. Thecomputer program product may comprise a non-transitory computer readablestorage medium on which the computer program is stored. For example, thecomputer program product may be a flash memory, a Random-access memory(RAM), a Read-Only Memory (ROM), or an EEPROM, and the computer programmodules described above could in alternative embodiments be distributedon different computer program products in the form of memories.

The disclosure has been described above with reference to embodimentsthereof. It should be understood that various modifications,alternations and additions can be made by those skilled in the artwithout departing from the spirits and scope of the disclosure.Therefore, the scope of the disclosure is not limited to the aboveparticular embodiments but only defined by the claims as attached.

What is claimed is:
 1. A method in a network device for facilitatingtransmission from a terminal device to the network device and at leastanother network device over bundled Transmission Time Intervals (TTIs),the method comprising: receiving from the terminal device a first TTIhaving a blanked portion for avoiding overlap with a second TTI fortransmission to a second network device; obtaining knowledge of theblanked portion based on a received signal power during the first TTI;and decoding the first TTI with the obtained knowledge of the blankedportion.
 2. The method of claim 1, wherein the blanked portion has alength that is a plurality of Orthogonal Frequency Division Multiplexing(OFDM) symbols.
 3. A network device for facilitating transmission from aterminal device to the network device and at least another networkdevice over bundled Transmission Time Intervals (TTIs) comprising: aprocessor; and a memory containing instructions which, when executed bythe processor, cause the network device to: receive from the terminaldevice a first TTI having a blanked portion for avoiding overlap with asecond TTI for transmission to a second network device; obtain knowledgeof the blanked portion based on a received signal power during the firstTTI; and decode the first TTI with the obtained knowledge of the blankedportion.
 4. The network device of claim 3, wherein the blanked portionhas a length that is a plurality of Orthogonal Frequency DivisionMultiplexing (OFDM) symbols.
 5. A non-transitory computer readablestorage medium comprising instructions which, when executed by aprocessor, cause a network device for facilitating transmission from aterminal device to the network device and at least another networkdevice over bundled Transmission Time Intervals (TTIs), to performoperations comprising: receiving from the terminal device a first TTIhaving a blanked portion for avoiding overlap with a second TTI fortransmission to a second network device; obtaining knowledge of theblanked portion based on a received signal power during the first TTI;and decoding the first TTI with the obtained knowledge of the blankedportion.
 6. The non-transitory computer readable storage medium of claim5, wherein the blanked portion has a length that is a plurality ofOrthogonal Frequency Division Multiplexing (OFDM) symbols.